Green Roofs for Urban Agriculture - Brighton Permaculture Trust

154 Pages·2008·3.03 MB·English

MSc Architecture:
Advanced Environmental and Energy
Studies

GREEN ROOFS FOR URBAN
AGRICULTURE

What is required to support their
implementation in the UK?

Hanna Waldbaum

January 2008

Hanna Waldbaum MSc Architecture Green Roofs for Urban Agriculture
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UNIVERSITY OF EAST LONDON

School of Computing and Technology

Longbridge Road
DAGENHAM
RM8 2AS
Tel. [phone]

Hanna Waldbaum MSc Architecture Green Roofs for Urban Agriculture
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Fig.1 Allotments on the roof of a block of flats (Source: The author)
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PREFACE

(Words written in italics in this section are explained in the glossary of terms)

This thesis is an investigation into what is required to introduce
green roofs for urban agriculture (agriroofs) in the UK with the
aim to include them in hundreds of new developments that are
presently planned for construction in towns and cities around the
country. Due to their complexity the provision of agriroofs
needs to be part of the design of a building from the start.

Agriroofs are accessible intensive green roofs which are
intended for food production, either as allotments or for
commercial production. They form part of urban agriculture, a
trend that has already started in deprived districts of some
cities around the world, and in one island country that was forced
by an embargo to become self-sufficient. These experiences
have shown that, similar to past allotment acts in the UK, planning
policies are needed to ensure agriroofs are introduced by law
wherever they are needed.

The urgency of this undertaking is prompted by the advent of
peak oil and climate change that is very likely to put an end to the
current, largely unsustainable, ways in which food is produced,
processed and distributed around the world at present.

To overcome the reluctance of the establishment to the
introduction of new elements in construction it is necessary to
present a convincing argument based on documented benefits
against expected financial outlay. The arguments in support of
agriroofs on new construction developments have been
investigated using data from research conducted on (the full
spectrum of) green roofs in other countries where these have
been in use over the past twenty years.

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All green roofs share certain characteristics. By replacing
traditional roof covers they provide additional insulation, they
slow down rain water runoff, provide habitats for biodiversity,
improve air quality, soften the townscape and have a beneficial
effect on the wellbeing of people.

Where obtainable, policies used in some countries have also been
studied. Legislation and policies in support of green roofs in this
country have been sought, but little was found.

The work of campaigners in the field of green roofs (sometimes
called living roofs) and in the field of urban agriculture has been
investigated as well.

Two key areas have been looked at to direct this move towards
green roof agriculture: case studies of a few existing projects
and the writing of a policy for agriroofs.

Field trips to existing ‘edible roof gardens’ in the UK and Austria
have provided inspiration and the material for case studies, the
findings of which have shown that roof agriculture is possible. It
became clear that a firm foundation in Local Development
Frameworks (LDF) is needed in order to facilitate the
introduction of agriroofs - as part of a general green roof policy
- in UK cities.

On the basis of these findings a policy proposal has been written
and sent out with a questionnaire to a selection of people involved
in relevant local government policy making.

The primary research in this thesis consists of the evaluation of
the responses received and conclusions drawn, which lead to a
revised policy proposal (2nd draft). A final (3rd) version follows
after further consultation with policy makers.

This thesis has limited its scope to new-build roofs; therefore
retrofitting has been left for further research, as it can also be
expected to become an issue in the near future.

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To be suitable for the growing of crops, a number of criteria
have to be met, such as easy accessibility, a minimum depth of
substrate, the provision of good drainage and sustainable means
of irrigation. Therefore only semi-intensive and intensive green
roofs are being considered for this purpose. The better known,
lighter extensive green roofs are mostly inaccessible and
designed for low-maintenance habitats. They are not suitable for
food growing and are therefore not included in the main study of
the thesis, although they are referred to, where useful.

Also excluded from the focus of this thesis is the growing of
plants in containers, which are traditionally used on roof gardens
and terraces and can be used for urban agriculture, but do not
fall under the definition of green roofs.

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ACKNOWLEDGEMENTS

First and foremost I wish to thank my tutor and thesis
supervisor Blanche Cameron whose support and encouragement
helped me overcome my initial writer’s block and whose
enthusiasm inspired me to explore new ground.
Many thanks also to Paul Early (author of an MSc thesis on green
roofs and co-author of CIRIA guidance book ‘Building Greener’)
whose library provided me with information and who proofread
the final draft of my thesis.
I am indebted to Dusty Gedge, founder of LivingRoofs.org, for
putting me in touch with green roof experts from abroad and for
his informative and entertaining talks on the subject.
I am very grateful to the twenty one respondents to my
questionnaire, who have given so generously of their time and
have provided much food for thought. Their names and
occupations are listed in Appendix 11.1.
Special thanks to Cllr. Jon Hooper, who informed and advised me
on policy writing; to Geoff Wilson whose website and e-mails have
provided me with information on green roofs in Australia, Asia
and Canada; to Dave Richards, Lidia Brandstätter, Wilhelm
Schlagintweit and Andreas Kraus for sharing their invaluable
insider information and for showing me around the impressive
green roofs that inspired and encouraged me to write this thesis.
Finally I wish to thank all my friends, my fellow AEES students
and my family for their much appreciated moral support that
helped me throughout the months of writing this thesis.

Hanna Waldbaum
20 January 2008

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TABLE OF CONTENTS

Preface 4
Acknowledgements 7
Table of contents 8
List of abbreviations 11
List of Figures 12
List of Tables 13
Glossary of terms 14
Introduction 17
1. The need for a solution 22
1.1 Peak Oil and Climate Change 22
1.2 The threat to food security 26
2. Urban food production 30
2.1 Roof space for urban food production
(Agriroofs) 32
2.2 Quantifiable savings 34
2.3 Intensive green roofs 37
2.4 Sustainable growing methods for agriroofs 40
3. Case studies 45
3.1 RISC Edible Roof Garden, Reading 46
3.2 Medicinal roof garden: Aspern Pharmacy,
Vienna 49
3.3 Rooftop allotments: Sargfabrik, Vienna 50
3.4 Rooftop allotments: One Brighton 52
3.5 Conclusions 53
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4. Green roof policies in some European countries 54
4.1 Linz, Austria 55
4.2 Vienna, Austria 57
4.3 Basel, Switzerland 59
4.4 Germany 60
4.5 Conclusions 60
5. Green roof policies in the UK? 62
5.1. The Mayor’s Biodiversity Strategy 62
5.2 The Code for Sustainable Homes 63
5.3 Planning Policy Statements 64
5.4 Sheffield Green Roofs Policy 65
5.5 Conclusions 65
6. Testing a policy proposal for green roofs
for urban agriculture 66
7. Evaluation of responses to the questionnaire
on the 1s policy draft 70
7.1 Analysis of responses to the 1st policy draft 70
7.2 Concerns expressed by respondents 77
7.2.1 Structural implications and cost 77
7.2.2 Water, leaks and drainage concerns 80
7.2.3 Health and safety concerns 81
7.2.4 Maintenance issues 82
7.2.5 Sustainability issues 83
7.2.6 Policy issues 83
7.3 Additions and suggestions from respondents 84
7.4 Conclusions 85

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8. The revised policy proposal 86
8.1 Testing the 2nd policy proposal 87
8.2 Conclusions 88
8.3 Policy proposal (final draft) 90
9. Conclusions 92
9.1 Final reflections 95
10. Limitations and recommendations 96
11. Appendices
11.1 List of respondents (Table 3) 98
11.2 Tabulation of responses (Tables 4 - 6) 100
11.3 A selection of completed questionnaires 112
11.4 ‘One Brighton’ case study questionnaire 128
11.5 RISC - The emergence of an Edible Roof Garden
(Figures 11 - 23) 131
11.6 Bauder - Maintenance procedure for intensive
green roofs 141
12. References 143
13. Bibliography 147

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